Aircraft navigational instrument



Dec. 25, i934. y R. H. SMITH 3,985,265

AIRCRAFT NAVIGATIONAL INSTRUMENT Filed April 2, 1932 4 Sheet-Sheet l of32 02W@ Il llllllllm;

Dec. 25, 1934. R. H. sMuTl- 3,935,265

v AIRCRAFT NAVIGATIONAL INSTRUMENT Filed April 2, 1932 4 sheets-sheet 3WIV INVENTOR ROBERT H. SM/TH ATTORNEY Dec. 25, 1934. R, H. 5mi-m3,985,265

AIRCRAFT NAVIGATIONAL INSTRUMENT Filed April 2, 1952 4 Sheets-Sheet 4Huh lllllh INVENTOR RUBERT H .5M/TH BY y ATTORNEY Patented Dec. 25,1934

'UNITED STATES PATENT OFFICE treated under theact of March 3,1883, as-

amendcd April 30, 1928; 370 0. G. '157) This invention relates tonavigational. instruments, and more particularly to aircraft deadreckoning positionindicators, by which a pilot in an aircraft can at aglance see his position and r,also know'the'bearing and distance of theaircraft carrier or other base of operation.

When single seated airplanes are operating from an aircraft carrier,either alone or in forma# tion, the duties of the pilots are so.multifarious as to" preclude navigation by the ordinary methods. Withthethrottle and controls to operate, a look-out to be kept, instrumentsto be observed and signals Ato be exchanged, a pilotin a singleV seatedplane has no time to manipulate a chart, parallel rulers and a pencil.This invention accomplishes, with a minimum of settings, thedetermination of the airplanes geographical lposition or positionrelative to some fixed or moving base of operation at all times. Theweight and-dimensions of the instrument are such that its'use in anairplane is entirely feasible.

' One of the most difficult problems in the navigation of the singleseated airplane occurs when operating at a distance at sea, withoutlandmarks, and from a moving aircraft carrier. There are three factorsaffecting the relative position of the airplane to the carrier: Thecourse andspeed of the carrier, the force and direction of the wind, andthe course and speed of the airplane. The navigation problem is toocomplicated to make a rough, quick calculation that can be relied upon,

and the importance -of locating the carrier at the' end of a night, whenthe gas is almost exhausted,

' is'too.l vital to permit of such practice and, as 'stated above,theduties of the pilot are such 'as to make it impossible to useordinary methods offnavigational plotting. Hence, 4the urgency of'providing some means to perform. this service is readily seen. Y

This inventionis so arranged as to indicate the geographical locationsor the relative positions of the carrierrand the plane at all times. Thethree factors are set on the machine, the niachine started, changes inthe `factors set on the machine at the time .ofv occurring, and thegeographical position and the bearing and distance` of the airplane fromthe carrier will be indicated Yat all times.

The objects of this invention are,.rst, toprovide an instrumentof.little,weight and small f dimensions whichv will indicate at alltimes the geographical locations or relative positions of `an aircraftcarrier and an airplane operating therefrom. .v

Second, to provide an instrument having one theftwo factors-aifectingthe airplane;

indicator that can be moved in accordance'w'ith the course and speed ofthe aircraft c rier .and another indicatorthat can be -moved inaccordance with the combined factors of the' course and speed of theairplane, together with the force-and l direction of the Wind. Y

Third, to provide a self-driven instrument for indicating the relativepositions of an airplane and the carrier from which it is flying uponwhich l the three' factors affecting theiry positions can l0 be set bysuitable knobs and dials.

With the above and other objects in view, this invention consists ofsuch construction and arrangement of parts as will be more fullydescribed hereinafter in connection with the accompanying drawings, inwhich:

Fig. 1 is a diagrammatic sketch of the apparatus for obtaining thedesired motions for the laircraft carrier indicator and for the airplaneindicator;

Fig. 2 is a diagrammatic sketchshowing the 20, indicators and theapparatus for applying the motions to them, together` with dials andknobs for setting the three involved factors on the instrument;

Fig. 3 shows one of the three graduated wheels 25 vfor setting speed ofairplane, speed of'carrier or force of the wind;

Fig. 4 shows an apparatus for securing a chart and which is adapted tobeinserted inA the machine of Fig. 2 directly under the intersecting 30Wires; Y

Fig. 5 shows the carrier indicator;

Fig. j'6 shows the airplane indicator;Y

Fig. '1 shows-a differential used in summing up Fig. 8 shows 'one of thefour clutches used in disconnecting the driving apparatus whilesettingthe position 'of the indicators by hand.

In Fig.Y 1,.the spring -motor 10 iscontrolled accurately as to speed,like a lclockwork mecha- '-nism, and isthe driving power of the entireapparatus. It drives primaryv toothed disk 11 at a constant speed which,in turn, by friction drives primary friction Wheel 12 at a speed that ispro-l portionate to its setting which may be -varied from the center tothe outside edge of the disk. The cog wheel 13 is sufliciently wide topermit this movement, and the adjustment is made in accordance with 'theair speed of the airplane as indicated on the dial on wheel 14. As wheel14 50 is turned, the nut 15 moves along shaft 16,-and the collar 17being connected to shaft 18 movesY 'the wheel 12. This is shown clearlyin Fig. 3. Having produced a motion which is -proportionate to the speedof the airplane, the next ,A

2 stepis to resolve it into two components, X and Y, at right angles toeach other. Secondary toothed disk 19 engages cog-wheel 13 and throughlbeveled gear 20 drives disk 21. The Y component 5 of the airplanesmotion is taken from toothed vmotion is imparted to wheel 22. When crank28 is at the side of disk 29, as seen .in Fig. 1, wheel 23 is at itsmaximum radius on disk 21 while secondary friction wheel 22 is Vat thecenter of secondary toothed disk 19. This corresponds to a course of twoseven zero or due west when the motion is all in the X direction withnone in the Y direction. Disk 29 is graduated from zero to 360 degrees.It is thus seen that as crank 28 is set to the angle corresponding tothe course of the airplane, that its motion is resolved through wheels23 and 22 into the proper X and Y components. The X motion is taken fromcog-wheel -30 by cog-Wheel 31 and through appropriate beveled gears isconnected to differential 32. 'I'he Y motion is taken from cog-wheel 33by cog-wheel 34 and through appropriate beveled gears is connected todifferential 35. The cogwheels 30 and 33 are wide enough to permit thefull movement of wheels 23 and 22 across the faces of disks 21 and 19respectively. Each slotted yoke is connected to its corresponding shaftby a swivel joint 119.

The next step is to produce a movement which bears the same relation tothe force of the wind as the first produced movement bears to the airspeed of the airplane. This movement is then split up into its X and Ycomponents and combined according to algebraic signs with the X and Ycomponents respectively of the airplane.

This is accomplished by engaging primary toothed disk 11 by a similarprimary toothed disk 36 which will be driven at the same constant speed.This in turn drives wheel 37 at a speed that isproportionate to itssetting which may be varied from the center to the outside edge of thedisk. The cog-wheel 38 is sufciently wide to permit this movement, andthe adjustment is made in accordance with the force of the wind, asindicated on the dial on Wheel 39. The apparatus and its operation issimilar to that used in setting the airplane speed by wheel 14. Thedirection of the wind is similarly set on disk 40 as the airplane courseis set on disk 29.

The motion representing the force of the wind is split up into its X andY components 4by apparatus similar to that used in splitting up themotion of the airplane, as may be seen by a reference to Fig. 1. These Xand'Y `components are likewise connected through suitable gears todifferentials 32 and 35 respectively. Differential 32 combines the two Xcomponents algebraically and differential 35 does the same for the Ycomponents. 'I'he resultant of these two] X components is taken from itsdifferential by shaft.41, and the corresponding resultant Y componentfrom its differential by shaft 42. These shafts, through suitable gears,move the airplane indicator in the X and Y direction asshown in Fig. 2.

'I'he motion of the\aircraft carrier is produced through a primary disk43 which, being connected directly to primary disk 36,v has the sameconstant speed as primary disk 11. Primary disk 43 drives primaryfriction wheel 44 at a speed which is'proportionate to its setting'whichmay be varied from the center to the outside edge of the disk. Cog-wheel45 is sufficiently wide tol permit this movement, and the adjustment ismade in accordance with the speed of the aircraft carrier as indicatedon the dial on Wheel 46. The apparatus and its operation is similar tothat used in setting the airplane speed by wheel 14. The course of theaircraft carrier is similarly set on disk 47 as the airplane course isset on disk 29. The motionv representing the speed of the carrier issplit up into its X and Y components by apparatus similar to that usedin splitting up the motion of the airplane, as may be seen in Fig. 1.The X components of the carriers motion'is taken from shaft 48, and theY component from shaft 49. These shafts, through suitable gears, movethe aircraft carrier indicator in the X and Y directions, as shown inFig. 2.

In order to reduce weight, it may be necessary to make the widecog-wheels 13, 33, etc., associated with the friction wheels 12, 22,etc., narrow. Each one could be slidingly keyed to its shaft and held inengagement with its associated cog-wheel by a forked arrangement.Another way to accomplish the same result would be to secure the shaft,secure a narrow cog-wheel to the shaft in place of the Wide one, and toobtain the desired motion by havingthe friction wheel slidingly keyed tothe shaft, the slotted yokes being connected to a forked arrangementthat controls the position of the friction wheel. i

When this apparatus is used in connection with a chart, the resultantmotions of the airplane and carrier indicators must correspond to thescale of the chart. When using mercator charts whose scale changes withthe latitude, the scales on 'wheels 14, 39 and 46 will have to bereplaced with new scales calibrated in accordance with the scale of thechart in use.

A type of differential which may be used for 32 and 35, Fig. l, is shownin Fig. 7. The motion of the two shafts 50 and 51 are combined to driveshaft 52. The beveled wheels 53 and 54 are united with their drivingcollars but are free to turn about, that is, not keyed to, shaft 52.

The revolving of beveled Wheels and 56 about the axis of shaft 52 causesit to rotate. If beveled wheel 53 rotates in one direction and beveledwheel 54 rotates at the same speed in the opposite direction, the shaft52 will not rotate, but if wheels 53 and 54 rotate in the samedirection, wheels 55 and 56 will revolve, and consequently shaft 52 willrotate at their combined speeds, which, if their speeds are equal, willbe double the speed of either one. Thus it will be seen that such adifferential will accurately combine the -wind and the airplanecomponents. In Fig. 2, the indicator 57 represents the airplane and ismoved according to the resultant of the airplane course and speed andthe force and direction of the Wind. 'Ihe indicator 58 is movedaccording to the course and speed of the aircraft carrier.'I'hese-indicators are moved by wires, the ends of which are secured tonuts that travel on threaded shafts.

Ihe shaft 41, Fig. 1, through suitable gears, drives a cog-wheel, notshown, which engages cog-wheel 59, Fig. 2, thereby driving threadedshaft 60 which, turn, through beveled gears 'plane motion,

6l, shaft 62 and beveled gears 63, drives threaded shaft 64. The beveledgear ratios being unity, lshafts and 64/ rotate at the same speed andare so threaded that nuts arid 66 move uniformly as regards speed anddirection, carrying the X- wire 67 so as to maintain it constantly'parallel to `its initial position, and through this wire imparting the Xmotion to the airplane indicator 57. The-shaft 42, Fig. 1, throughsuitable gears, drives a cog-wheel, not shown, which engages cog-wheel68, Fig. 2, thereby driving threaded shaft 69, which, in turn, throughbeveled gears 70, shaft 71 and beveled gears 72, drives threaded shaft73. The beveled gear ratios being unity, shafts 69 and 73 rotate at thesame speed and are so threaded that nuts 74 and 75 move uniformly asregards speed and direction, carrying the Y wire 76 so as to maintain itconstantly parallel to its initial position which is at right angles towire 67;J and through this wire 76 imparting the Y motion to theairplane indicator 57. Thus itwill be seeii that the airplane indicatoris maintained at the 'intersection of wires 67 and 76, giving it X and Ycomponents proportionate to those of the airand hence, its resultantmotion is correspondingly proportionate to the airplane motion.

The shaft 48, Fig. 1, through suitable gears, drives cog-wheel v77, thatengages cog-wheel 78, and through it driving threaded shaft 79 which, inturn, through beveled gears 80, shaft 81 and beveled gears 82 drivesthreaded sh'aft 83. The shafts `79 and 83 rotate at 'the -same speed andmove the nuts 84 and 85 uniformly as regards speed and direction,carrying the X wire 86 so as to maintain it constantly parallel to itsinitial position and through thiswire imparting the X motion to theaircraft carrier indicator 58. The shaft 49, Fig. 1 through suitablegears, drives cog- ,wheel 87 that engages-cog-wheel 88 and through itdriving threaded shaft 89 which, in turn,

through beveled gears 92 drives threaded shaft 93. The shafts 89 and 94rotate at the same speed and move the nuts .94 and 95 uniformly. asregardsspeed andA direction,` carrying the Y wire 96 so as Yto maintainit constantlyparallel to its initial position which is at right anglesto wire 86, and through thiswire 96 imparting the Y motion to 'theaircraft'carrier indicator 58. -Thus it will be seen that the aircraftcarrier indicator is maintained at the intersection of wires 86 and 96,giving it X and Y components proportionate to those `of the carriermotion, and hence, its resultant motion is correspondingly proportionateto the earriers `motion.,

The two X wires 67 and 86 and the two Y wires 76 and 96 are parallel toeach other andthe guides 97 allow the wire-carrying nuts longitudinalmotion but prevent their .turning on their respective shafts. Y Y

Normally, the airplane'will start from the carrier and indicator 57 willbe set directly over indicator 58, butregardless of whether orA not theyleave from the same point, their initial geographical positions orrelative positions will have to be set on the machine.

To do this, handles 98 and clutches 99 are provided with each X and Ymechanism. In setting the 'X wires of the'carrier, cogwheel 78 is pulledto the left disengaging it from cog-wheel 77, and the crank turned asnecessary to move the Xwire 86 tothe desired initial position. The otherX and Y wires are similarly set. The clutch 99 will be further describedin connection with Fig. 8. j f

ranged conveniently near the front of the instrument, as shown 100, 101and 102, and the course or direction disks 29, 40 and 47 are controlledby conveniently arranged dials 103, 104 and 105. When these have allbeen set, the mototl l0 is started. As changes occur in the factors seton the machine, the proper dials will be correspondingly adjusted. Theindicator 58 will then follow the consecutive positions of the carrier,and the indicator 57 the consecutive positions of the airplane. As theindicators separate, wire 106 will be drawn out, as will be describedlater, the length of this wire indicating the distance between thecarrier and the airplane, and the bearing of the carrier from theairplane being indicated by this wire on the graduated disk of indicator57. Of course, this bearing is not the proper course to steer tointerceptthe carrier, as account must be taken of the courseu and speedof the carrier. But an attempt should be made to put the airplane on acollision course, the same being set on the machine. If successful, asthe airplane approaches the can'ier the hear-v ing will not change. If,however, the relative bearing increases or decreases, the course shouldbe changed accordingly until the bearing is constant, when the observedcourse should be mainvwhich fits snugly into forked piece 108 of theclutch. These pieces are pressed together by spring 109 acting onbearing 110 and piece 108. When setting the machine by hand, handle 98is pulled out until cog-wheel 78 is disengaged from cog-wheel 77, Fig.2, spring 109 being fully compressed, but forked piece 108 stillengaging the end of tongue piece 107 through which the shaft 97-isturned. When adjusted, handle 98 is then pressed in until cog-wheel 78engages cog-wheel 77, Fig. 2. During operation the spring 109'main-`tains this engagement.

In Fig. 5 the carrier indicator 58, Fig. 2, is shown in 'greater detail.The wire 106. Fig. 2, passes down through hole 111 and winds up on drum112 which is provided. with a spring to keepv the wire taut on the drumand maintain a proper tension on it as it is pulled out. The X wire 86,Fig. 2, passes through hole 114 and the Y wire 96, Fig. 2, passesthroughhole 113.

In Fig. 6, the airplane indicator, Fig. 2, is shown in greater detail.The wire 106, Fig.'2, is attached at point 116 at the bottom of theindicator. The. machine is soconstructed that the low'er part ofindicator 57 passes just-over reference vessel is near the center of theappa- -ratus or near one edge, if known in advance that the movements ofboth airplane and reference vessel will be away-from that edge.Insetting the indicator, the wires vare moved until they intersect atthe proper points the scales. of latitude 'and longitude marked on thechart.

' Another use ofthe instrument is in checking' the compass. The airplanein fair weather flies keep on'the direct line between them. Th'e-true IA course by compass is s'et on the instrument, the 'I'he speed dials 14,39 and 46, Fig. 1, are arindicator 57 being set over the initial point.

between' two points with markers to followto When the plane arrives atthe second point, the indicator should be over the second point on thechart. If not, the bearing indicated by wire 106 is noted, the indicator57 is moved until it is over the second point and the change in bearingindicated by wire 106 is noted. This change is the error in the initialcorrection applied to the While in the foregoing there has beenillustrated and described such combinations and arrangements of elementsas constitute the preferred embodiment of my invention, it isnevertheless desired to emphasize the fact that interpretation oftheinvention should be conclusive only when made in the light of thesubjoined claims.

'I'he invention described herein may be manufactured and used by or forthe Government of the United States of America for governmental purposeswithout the payment to me of any royalties thereon.

--Iclaimz -motion into two mutually normal vectors, a second indicator,means positioning said second indicator in accordance with the resultantof said last two vectors,v and means jointly controlled by said twoindicators for giving the course from one to the other, allvectors.being to substan of said `first and second motion, means forcausing a second indicator to move in accordance with the X and Ycomponents of said third motion, and means cooperating withsaid-indicators to indicate the location of said second indicator inrelation to said first indicator.

memes V 3. A navigational instrument, comprising a constant speed motor,three constant speed primary disks driven by said motor, a primaryfriction wheel adjustable radially of each primary disk, a first, asecond, and a third set of secondary disks driven respectively by saidprimary friction wheels, a ilrst. a second and a third set of secondaryfriction wheels each adjustable radi- .allyof its correspondingsecondary disks, a first and second resolving means for adjustingrespectively said rst and second sets of secondary friction wheelsradially of said corresponding secondary disks, and ilrst and seconddifferentials for combining corresponding parallel ymotions from saidfirst and second sets of secondary friction wheels.

4. A navigational instrument, comprising a first and a second set ofthreaded shafts, all parallel to each other, a third and,a fourth set ofthreaded shafts ail parallel to each other and at right angles to saidfirst and second sets of shafts, all of said sets of shafts being drivenby a common source of power, a nut movable along and a guide for saidnut associated with each of said threaded shafts,` a wire extendedbetween the nuts of corresponding shafts of opposed pairs, a firstindicator adapted to be maintained at the intersection of the wiresextending between the first and third set of shafts, and a secondindicator adapted to be maintained at the intersection of the wiresextending between the second and fourth sets of shafts.

5. A navigational instrument, comprising a constant speed motor, threeconstant speed primary disks driven by said motor,aprimaryfriction wheeldriven by each primary disk, means for arljusting said primary frictionwheels radially of said primary disks respectively in accordance withair speed of an airplane, velocity of the wind and speed of a referencevessel, a rst, a second, and a third pair of secondary disks drivenrespectively by said primary friction wheels, a first, a second, and athird pair of secondary friction wheels each driven by its correspondingsecondary disk, three double slotted yoke crank mechanisms each adaptedto convert circular motion into rectilinear motion in two directions atright angles to each other for adjusting each pair of secondary frictionwheels radially of said corresponding secondary disks in accordance'with the course of an airplane, direction of the wind and course of areference vessel, and first and seconddiiferentials for combiningcorresponding parallel components from said first and second pairs ofsecondary friction wheels.

ROBERT HALL SMITH.

